Advanced Water Management Centre (AWMC), The University of Queensland, Brisbane, Qld 4072, Australia.
Environ Microbiol Rep. 2009 Oct;1(5):377-84. doi: 10.1111/j.1758-2229.2009.00083.x. Epub 2009 Sep 23.
The microorganisms responsible for anaerobic oxidation of methane (AOM) coupled to denitrification have not been clearly elucidated. Three recent publications suggested it can be achieved by a denitrifying bacterium with or without the involvement of anaerobic methanotrophic archaea. A key factor limiting the progress in this research field is the shortage of enrichment cultures performing denitrifying anaerobic methane oxidation (DAMO). In this study, DAMO cultures were enriched from mixed inoculum including sediment from a freshwater lake, anaerobic digester sludge and return activated sludge from a sewage treatment plant. Two reactors, operated at 35°C and at 22°C, respectively, showed simultaneous methane oxidation and nitrate reduction after several months of operation. Analysis of 16S rRNA gene clone libraries from the 35°C enrichment showed the presence of an archaeon closely related to other DAMO archaea and a dominated bacterium belonging to the yet uncultivated NC10 phylum. This culture preferred nitrite to nitrate as the electron acceptor. The present study suggests that the archaea are rather methanotrophs than methanogens. The highest denitrification rate achieved was 2.35 mmol NO3 (-) -N gVSS(-1) day(-1) . The culture enriched at 22°C contained the same NC10 bacterium observed in the culture enriched at 35°C but no archaea.
负责与反硝化作用偶联的厌氧甲烷氧化（AOM）的微生物尚未得到明确阐明。最近有三篇论文表明，这可以通过一种具有或不涉及厌氧甲烷营养型古菌的反硝化细菌来实现。限制该研究领域进展的一个关键因素是缺乏进行反硝化厌氧甲烷氧化（DAMO）的富集培养物。在这项研究中，从包括淡水湖沉积物、厌氧消化污泥和污水处理厂回流活性污泥在内的混合接种物中富集 DAMO 培养物。两个反应器分别在 35°C 和 22°C 下运行，经过数月的运行后，同时进行甲烷氧化和硝酸盐还原。对 35°C 富集物的 16S rRNA 基因克隆文库进行分析表明，存在一种与其他 DAMO 古菌密切相关的古菌，以及一种属于尚未培养的 NC10 门的优势细菌。该培养物更喜欢亚硝酸盐作为电子受体，而不是硝酸盐。本研究表明，这些古菌更像是甲烷营养菌而不是产甲烷菌。达到的最高脱氮速率为 2.35mmol NO3 (-) -N gVSS(-1) day(-1) 。在 22°C 富集的培养物中含有与在 35°C 富集的培养物中观察到的相同的 NC10 细菌，但没有古菌。
